Ancient Egyptians insisted that every child in the family should inherit the same amount of land or money when their parents died - both brothers and sisters. This was unusual in ancient times, when in most places only the boys could inherit land. It was a big help to the girls, who could support themselves without having to depend on men.
The Egyptians themselves had some problems with this rule. Some families didn't like the idea that girls would take their part of the family farm with them into another family when they got married. So sometimes in ancient Egypt girls married their brothers, to keep the land in the family.
We have the records of one lawsuit, where a married woman is suing her brother because he is refusing to give her her fair share of their fathers' property. (Papyrus Brooklyn 35.1446, from the late Middle Kingdom, now in the Brooklyn Museum).
To find out more about families in ancient Egypt, check out these books from Amazon or from your library:
Everyday Life in Ancient Egypt, by Lionel Casson (revised edition 2001). Not especially for kids, but pretty entertaining reading, and Casson knows what he's talking about.
Private Life in New Kingdom Egypt, by Lynn Meskell (2002). A little more specialized and harder to read.